The present invention relates to an electrically connectable adhesive agent for a semiconductor.
Conventionally, a wire-bonding system has been widely employed in order to interconnect an integrated circuit. However, as a connection density becomes higher, there arise limits of a pitch according to the wire-bonding system. Therefore, flip chip method is commonly employed, in which solder bumps are disposed over the area of a chip, and the chip is rendered bottom up, and is connected to a substrate.
Flip chip method commonly comprises the steps of: applying a fluxing agent to a substrate in order to bind a circuit to the substrate; aligning a chip having a solder bump, reflowing the solder by heating to connect the chip having a solder bump and the substrate each other. At this time, the fluxing agent removes an oxide film of a copper foil on the surface of the substrate and the solder to assist the connection by soldering. After the chip having a solder bump and the substrate were connected to each other according to the step of reflowing, it is necessary to wash up all the residual fluxing agent, which will cause corrosion.
After all the residual fluxing agent is washed up, a liquid sealing agent is injected from the side. The connection between the chip having a solder bump and the substrate is completed by heating and hardening the sealing agent.
R. W. Pennisi et al. reported the use of an adhesive agent providing excellent flux effects without washing up the residual fluxing agent. However, there exists a problem that wettability to a solder is decreased, and a filler can not be included therein. Therefore, there is a problem for the reliability thereof as an adhesive agent.
It is an object of the present invention to provide an adhesive agent, which has high reliability and a flux effect if it is used as a sealing agent for an epoxy flip chip.
The present invention relates to an electrically connectable adhesive agent for a semiconductor, which comprises an epoxy resin, an acid anhydride curing agent, a curing accelerator and a butadiene-acrylonitrile rubber containing a carboxyl group.
The adhesive agent for a semiconductor preferably comprises a filler.